Abstract
Objective: To assess outcomes and complications of stereotactic radiosurgery treatment for trigeminal schwannoma (TS). Methods: A retrospective analysis was performed to describe the presentation and outcomes of patients undergoing Gamma Knife radiosurgery (GKRS) for TS. Clinical, radiographic, and stereotactic radiosurgery dose plans were reviewed. Descriptive statistics and univariate analysis were performed to identify factors associated with poor tumor control. Results: A total of 22 patients with TS were treated with GKRS between 1990 and 2018. One patient had a history of neurofibromatosis type II. Of the study population, 81% underwent GKRS as a first-line treatment. The average tumor volume was 3.3 cm3 and the average margin treatment dose was 14.1 Gy. The median clinical and radiographic follow-up period were 18.5 and 27 months, respectively. Tumor control was achieved in 17 patients (77.3%). Symptomatic improvement was noted in 8 patients (42.1%). Tumor expansion was observed in 7 patients (31.8%) and was associated with poor tumor control at last follow-up (P < 0.05). Patients who developed transient tumor expansion had higher margin doses (14.9 ± 1.1 Gy) compared with patients who did not have expansion (13.6 ± 1.3 Gyk P < 0.05). Conclusions: GKRS provides effective control for most TS. Increased margin doses are associated with tumor expansion, which was a poor prognostic event associated with progression and clinical decline. Based on these results, combined with analysis of available data from other series of TS treated with GKRS, we believe that margin dose between 13 and 14 Gy offers a high probability of tumor control, yet minimizing risk of adverse radiation effects. © 2018 Elsevier Inc.